mysql_stmt_attr_set - Sets attribute of a statement
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#include <mysql.h>
my_bool mysql_stmt_attr_set(MYSQL_STMT * stmt,
enum enum_stmt_attr_type,
const void * attr);
Used to modify the behavior of a prepared statement. This function
may be called multiple times to set several attributes. Returns zero on
success, non-zero on failure.
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- stmt - a statement handle, which was previously
allocated by mysql_stmt_init(3).
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- enum_stmt_attr_type - the attribute that you want
to set. See below.
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- attr - the value to assign to the attribute
The enum_stmt_attr_type attribute can have
one of the following values:
Value |
Type |
Description |
STMT_ATTR_UPDATE_MAX_LENGTH |
my_bool * |
If set to 1, mysql_stmt_store_result(3) will update the
max_length value of MYSQL_FIELD structures. |
STMT_ATTR_CURSOR_TYPE |
unsigned long * |
cursor type when mysql_stmt_execute(3) is invoked. Possible
values are CURSOR_TYPE_READ_ONLY or default value
CURSOR_TYPE_NO_CURSOR. |
STMT_ATTR_PREFETCH_ROWS |
unsigned long * |
number of rows which will be prefetched. The default value is 1. |
STMT_ATTR_PREBIND_PARAMS |
unsigned int * |
number of parameter markers when using
mariadb_stmt_execute_direct(3). If the statement handle is reused
it will be reset automatically to the state after mysql_stmt_init(). This
option was added in Connector/C 3.0 |
STMT_ATTR_ARRAY_SIZE |
unsigned int * |
number of array elements. This option was added in Connector/C 3.0 and
requires MariaDB 10.2 or later |
STMT_ATTR_ROW_SIZE |
size_t * |
specifies size of a structure for row wise binding. This length must
include space for all of the bound parameters and any padding of the
structure or buffer to ensure that when the address of a bound parameter
is incremented with the specified length, the result will point to the
beginning of the same parameter in the next set of parameters. When using
the sizeof operator in ANSI C, this behavior is guaranteed. If the value
is zero column-wise binding will be used (default). This option was added
in Connector/C 3.0 and requires MariaDB 10.2 or later |
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- If you use the MYSQL_STMT_ATTR_CURSOR_TYPE option
with MYSQL_CURSOR_TYPE_READ_ONLY, a cursor is
opened for the statement when you invoke mysql_stmt_execute(3). If
there is already an open cursor from a previous
mysql_stmt_execute(3) call, it closes the cursor before opening a
new one. mysql_stmt_reset(3) also closes any open cursor before
preparing the statement for re-execution.
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- If you open a cursor for a prepared statement it is unnecessary to call
mysql_stmt_store_result(3).
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- mysql_stmt_free_result(3) closes any open cursor.
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- mariadb_stmt_execute_direct(3)
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- mysql_stmt_attr_get(3)